(1) Prior to and including 1976, the term relationship to head was used.

(2) The term head was considered inappropriate and relationship to Person 1 was asked.

(3) Since 1986 relationship to Person 1/Person 2 has been asked.

(4) Year of first marriage was used.

(5) Prior to 1976, nationality rather than citizenship was asked.

(6) Since 1986 the person has been asked whether or not they were an Australian citizen.

(7) In all censuses prior to 1971, respondents were required to state their race and, where race was mixed, to specify the proportion of each.

(8) In the 1971 and 1976 Censuses, a question with response categories of European, Aboriginal, Torres Strait Islander and Other was included.

(9) A question on each person's ancestry was asked for the first time in 1986.

(10) The 1961 Census asked for state of usual residence.

(11) State level only.

(12) Question asked whether the person could read and write.

(13) Question asked whether the person could read and write a foreign language if unable to read and write English.

(14) The 1976 Census asked for all languages regularly used.

(15) In 1981 ability to speak English was asked.

(16) Since 1986 two separate questions have been asked - language used and ability to speak English.

(17) Included a question where respondents reported their highest level of educational achievement.

(18) Since 1976, a question on attendance at school or other educational institution has been asked.

(19) Since 1971, people aged 15 or more have been asked whether they had obtained a qualification. If so, information on the name of highest qualification obtained, field of study, the name of institution and the year obtained was collected.

(20) In the Censuses from 1981 to 1996, respondents have been required to answer a series of questions from which labour force status was coded.

(21) An additional question - main tasks or duties performed in the occupation has been asked from 1986 to 1996.

(22) Place of work was first collected in 1954.

(23) Employer's occupation was asked in 1911 and 1921.

(24) 1971, 1976 and 1996 Censuses focused on hours worked in all jobs held in the week prior to the census.

(25) The 1981, 1986 and 1991 Censuses asked for hours worked in the main job in the week prior to the census.

(26) Journey to work topic has been derived from coding of address of usual residence and address of workplace to obtain origins and destinations of travel to work.

(27) Data was collected but not processed.

(28) From 1911 to 1971, and in 1996, a direct question on nature of occupancy was asked.

(29) From 1976 to 1991, nature of occupancy data was derived from mortgage and rent questions.

(30) If paying rent to a Government Authority in 1954 or a State Housing Authority in 1961, respondents were instructed to write 'Tenant (G)'.

(31) Tenants in 1966 had the option of marking the relevant State Housing Authority or 'other landlord'.

(32) In 1971, response categories comprised State Housing Authority, employer or other landlord.

(33) The number of landlord response categories rose from three (from 1971 until 1991) to seven in 1996.

(34) In 1976 the monthly payment made on first and second mortgages was asked.

(35) Average monthly payment for total mortgages was asked.

(36) Monthly payment made on the loans for the dwelling was asked.

(37) Those with mortgage repayments had the option of writing the weekly, fortnightly or monthly amount paid.

(38) This question has been completed by the Census Collector since 1976.

(39) In 1996 a new classification was developed for Other Dwellings. It included caravans in caravan parks, boats in marinas, anufactured home estates and self-care units in accommodation for the retired or aged, all of which were enumerated using household forms. However in 1986 and 1991, caravans in caravan parks and boats in marinas were included in the Non-Private Dwelling classification.

(40) The question was answered by the Census Collector in 1981.

(41) In 1976, type of fuel or power used for household purposes was asked.